1. Field of the Invention
Embodiments of the present invention relate to customer premises equipment. More particularly, embodiments of the present invention relate to systems and methods for an electronic hook switch for customer premises equipment.
2. Background Information
While telephone infrastructure varies from country to country, the United States infrastructure provides a useful starting point for purposes of describing background information and embodiments of the present invention. Naturally, the embodiments described herein are useful in other contexts. In the United States, a landline phone can be a cordless or corded telephone that is coupled to a central office (“CO”) of a local exchange carrier (“LEC”) such as a Regional Bell Operating Company (“RBOC”), a competitive local exchange carrier (“CLEC”), and so on. Cordless telephones have no cord between the handset and base, each of which have a radio transmitter, receiver and antenna for communications between the handset and base. Typically, the handset includes a rechargeable battery, and the base is powered by current from an alternating current (“AC”) outlet (e.g., of a house, office, etc.). The range of effective communications between the handset and base can be from 10 feet to several miles depending on factors such as product design, operating radio frequency(s), environmental conditions, and legal restrictions (e.g., laws, regulations, etc.). Examples of known operating radio frequencies for cordless telephone communications in the United States include 900 Megahertz (“MHz”), 2.4 Gigahertz (“GHz”), 5.8 GHz, a combination thereof, and so on.
In a residential environment, the base is typically coupled to the CO via one or more wires, such as an RJ-11 wire that couples the base to an RJ-11 jack on a wall or in a floor. The RJ-11 jack is typically coupled to the CO via a twisted-pair wire. The CO can provide voltage and current to a telephone coupled to the CO via the RJ-11 wire and the RJ-11 jack. For example, known corded phones draw power from the CO during telephone call dialing and during the telephone call. Each RJ-11 jack usually has four wires, which consist of two sets of a tip and ring pair. A single-line corded phone is typically coupled to one set of a tip and ring pair (and can draw power from that tip and ring pair), and a two-line corded phone is typically coupled to each of the two sets of the tip and ring pairs (and can draw power from either or both tip and ring pair).
As used to describe the background and embodiments of the present invention, the term “coupled” encompasses a direct connection, an indirect connection, or a combination thereof. Two devices that are coupled can engage in direct communications, in indirect communications, or a combination thereof. Moreover, two devices that are coupled need not be in continuous communication, but can be in communication typically, periodically, intermittently, sporadically, occasionally, and so on. Further, the term “communication” is not limited to direct communication, but also includes indirect communication.
Cordless phones typically do not draw power from the tip and ring pairs because the cordless phone base is powered by current from an AC outlet. Cordless phones, however, are still connected to one or more of the tip and ring pairs to transmit and receive voice and data communication signals. Moreover, a cordless phone base includes electronic circuitry that is powered at a relatively low voltage as compared to the voltages associated with a tip and ring pair. For example, electronic circuitry is often powered at 12 volts, 5 volts, 3.3 volts, and so on. In contrast, voltages associated with a tip and ring pair can be as high as 350 volts.
In known telephones, an electronic hook switch consists of a high side switch and a low side switch, so that a low voltage control integrated circuit (“IC”) (e.g., a microcomputer unit, a dialer IC, a specific controller, etc.) can control the electronic hook switch notwithstanding the high voltage between tip and ring. In such known systems, whether or not they are constructed using bipolar transistors or MOSFETs, neither the high side switch nor the low side switch is omitted. Because these systems have both a high side switch and low side switch, there are disadvantageous cost and system design implications.
For example, known customer premises equipment (“CPE”), such as a telephone, usually employs two Darlington connected PNP transistors to build the high side switch and have one NPN transistor for the low side switch. If P-channel MOSFET is used for the high side switch, an N-channel MOSFET is required for the low side switch to translate the line voltage level to a voltage low enough to interface with the control circuit. Often, each of the low side switch and the high side switch have to withstand voltages as high as 350 volts. In view of the foregoing, it can be appreciated that a substantial need exists for systems and methods that can advantageously provide for an electronic hook switch for customer premises equipment.